THAT Supreme alone and is One only - Kathopanishad 2.2.12
एको वशी सर्वभूतान्तरात्मा एकं रूपं बहुधा यः करोति ।
तमात्मस्थं ये'नुपश्यन्ति धीरास्तेषां सुखं शाश्वतं नेतरेषाम् ॥ १२ ॥
Eko basee sarba bhutaanta raatmaa ekam roopam bahudhaa jah karoti
tam aatmastham je anupashyanti dheera stesaam sukham shaashwatam netaresaam
The Kathopanishad 2.2.12
That Supreme alone and is one only. He is the controller and provider of all. He is the Inner Self of all beings. He, creates infinite number of forms (beings) from His Oneness only. Those spiritual seekers who perceive Him in their own hearts, really enjoy Eternal Bliss. None else can enjoy That Bliss.